The BAL-binding protein BBAP and related deltex family members exhibit ubiquitin-protein isopeptide ligase activity

Kunihiko Takeyama, Ricardo C.T. Aguiar, Liqun Gu, Chunyan He, Gordon J. Freeman, Jeffery L. Kutok, Jon C. Aster, Margaret A. Shipp

    Research output: Contribution to journalArticle

    71 Scopus citations

    Abstract

    Members of the DTX (Deltex) family act as Notch signaling modifiers and may also regulate transcription through interactions with specific transcription factors. DTX proteins have a basic N terminus; a central proline-rich region; and a C-terminal RING finger domain, a motif often found in ubiquitin-protein isopeptide ligases (E3). Recently, we identified and characterized a unique diffuse large B-cell lymphoma risk-related gene named BAL (B aggressive lymphoma). Using a yeast two-hybrid screen for BAL-binding partners, we have now identified a novel protein termed BBAP (B-lymphoma- and BAL-associated protein). Although BBAP has a unique N terminus, the C-terminal region is highly homologous to that of DTX family members. Herein, we report that BBAP and the human family of DTX proteins (DTX1, DTX2, and DTX3) function as E3 ligases based on their capacity for self-ubiquitination. DTX family members homodimerize and heterodimerize in vivo, suggesting that physical interactions between various DTX family members modify E3 activity and/or substrate availability. Consistent with this idea, BBAP and DTX1 associate via their unique N termini, resulting in enhanced self-ubiquitination.

    Original languageEnglish (US)
    Pages (from-to)21930-21937
    Number of pages8
    JournalJournal of Biological Chemistry
    Volume278
    Issue number24
    DOIs
    StatePublished - Jun 13 2003

    ASJC Scopus subject areas

    • Biochemistry
    • Molecular Biology
    • Cell Biology

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    Takeyama, K., Aguiar, R. C. T., Gu, L., He, C., Freeman, G. J., Kutok, J. L., Aster, J. C., & Shipp, M. A. (2003). The BAL-binding protein BBAP and related deltex family members exhibit ubiquitin-protein isopeptide ligase activity. Journal of Biological Chemistry, 278(24), 21930-21937. https://doi.org/10.1074/jbc.M301157200